An offset or asymmetrical self-contained liquid metal current collector for cyclic or homopolar electrical generators or motors is provided which includes a narrow annular volume on one side and a wide annular volume on the other side of the collector disc. Selectively positioned circular troughs effectively communicate with each other so that the liquid metal is trapped and retained when the rotating speed of the disc is too low to centrifugally maintain the liquid metal at the outer periphery of the disc.